Rapid prototype extruded conductive pathways

ABSTRACT

A process of producing electrically conductive pathways within additively manufactured parts and similar parts made by plastic extrusion nozzles. The process allows for a three-dimensional part having both conductive and non-conductive portions and allows for such parts to be manufactured in a single production step.

RELATED APPLICATIONS

This application claims the benefit of U.S. Application Ser. No.61/562,784, entitled “Rapid Prototype Extruded Conductive Pathways”,filed on Nov. 22, 2011, and which is incorporated herein by reference.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH AND DEVELOPMENT

This invention was made with Government support under Contract No.DE-AC09-08SR22470 awarded by the United States Department of Energy. TheGovernment has certain rights in the invention.

FIELD OF THE INVENTION

This invention is directed towards a process of producing electricallyconductive pathways within rapid prototyping parts and similar partsmade by plastic extrusion nozzles. The process allows for athree-dimensional part having both conductive and non-conductiveportions and allows for such parts to be manufactured in a singleproduction step.

BACKGROUND OF THE INVENTION

This invention relates generally to products and substrates havingconductive and non-conductive portions. Representative patents onmaterials having conductive and non-conductive portions include:

U.S. Pat. No. 6,951,233 to Calvar discloses materials having aconductive band within a non-conductive material. The process allowsextrusion of conductive and non-conductive materials at the same timebut extrudes materials in a straight line and does not offer an abilityto extrude complicated conductive shapes and traces.

U.S. Pat. No. 4,858,407 is directed to extruding semi-conductive andnon-conductive heat layers on an electrical cable. The extruded layersare essentially cylinders and are concentric. There is no inter-mixingof materials and non-linear products can not be made.

U.S. Pat. No. 5,133,120 provides a method to fill a hole on a circuitboard with a conductive paste. The conductive paste joins conductivelayers within the circuit board following circuit board production.

U.S. Pat. Nos. 5,925,414 and 6,132,510 are directed to extruding aconductive paste through a stencil or screen onto an essentially planarsurface. The method within these patents will not produce athree-dimensional conductive pathway or permit formation of a desiredpart in, a single step.

U.S. Application 2006/0063060 teaches extrusion of a conductive materialsuch as graphite through a non-conductive substrate to produceconductive pathways through a substrate. The extrusion is a secondaryprocess that requires assembly of the graphite substrate andnon-conductive substrate.

There remains room for improvement in variation within the art.

SUMMARY OF THE INVENTION

It is one aspect of one of the present embodiments to provide for amethod and process of producing an electrically conductive pathwaywithin a three-dimensional part made by a rapid prototype extrusionmachine or a rapid additive manufacturing machine.

It is a further aspect of at least one of the present embodiments of theinvention to provide for a process and method extrude a part havingconductive and non-conductive material made by selectively extrudingconductive materials within desired regions on each layer of the part.The extrusion of the conductive material may be made through the use ofa separate extruder head containing a conductive material.

It is a further aspect of at least one of the present embodiments toprovide for a three-dimensional substrate having conductive andnon-conductive electrical pathways in which the conductive portions areformed through the addition of a conductive material during extrusion,the conductive material including conductive metals such as stainlesssteel fibers, copper fibers, other metallic fibers, or the use ofnon-metallic conductive materials such as carbon, carbon nano tubes,carbon nanoparticles and conductive polymers.

It is a further aspect of at least one of the present embodiments of thepresent invention to provide for an electrically conductive pathwaywithin a three-dimensional extruded part using conductive powder layersapplied during extrusion of a part. As used herein, the term“three-dimensional” additionally includes three-dimensional substratesthat have a non-uniform shape or geometry with respect to either thefinal substrate shape and/or to the shape of a respective conductive ornon-conductive region or regions within the substrate.

It is a further aspect of at least one of the present embodiments of thepresent invention to provide for an electrically conductive pathwaywithin a three-dimensional part, which the part is created by aplurality of layers of powders held together with a binder, usuallyapplied in an ink jet manner. When desired, the binder can include aconductive filler, such conductive fillers including nano tubes. Theprocess allows conductive pathways to be printed and/or within the partcreated by the sequential formation of the respective powder layers andbinders, using conductive and non-conductive binder as appropriate tocreate the conductive pathways.

It is a further aspect of at least one of the present embodiments of thepresent invention to provide for a process of providing athree-dimensional part having selected areas of electrical conductivityand non-conductivity comprising the steps of:

supplying one of either a rapid prototype extrusion machine or a rapidadditive manufacturing machine; and

extruding a three-dimensional part comprising a first portion which iselectrically non-conductive and a second portion which is electricallyconductive, the second portion including a mixture of a non-conductivesubstrate with an electrically conductive substrate.

It is a further aspect of at least one of the present embodiments of thepresent invention to provide for a process of providing a multi-layeredobject having areas of electrical conductivity and electricalnon-conductivity comprising the steps of:

forming a non-conductive substrate by the deposition of multiplesubstrate layers;

integrating within the multiple substrate layers of the non-conductivesubstrate at least one three-dimensional region of a conductivesubstrate, the conductive substrate applied by one of the either stereolithography, laser sintering, ink-jet printing, or fused deposition;

wherein the multi-layered object has a three-dimensional electricalconductive portion within the non-conductive substrate.

These and other features, aspects, and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the embodiments of theinvention, one or more examples of which are set forth below. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used on another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncover such modifications and variations as come within the scope of theappended claims and their equivalents. Other objects, features, andaspects of the present invention are disclosed in the following detaileddescription. It is to be understood by one of ordinary skill in the artthat the present discussion is a description of exemplary embodimentsonly and is not intended as limiting the broader aspects of the presentinvention, which broader aspects are embodied in the exemplaryconstructions.

In accordance with this invention, any number of rapid prototypingapparatuses can be modified as set forth herein to carry out a processfor formation of a three-dimensional object having conductive andnon-conductive portions therein. U.S. Pat. No. 7,896,639 to ObjetGeometries Ltd. describes an apparatus using multiple printing heads forsequentially forming thin layers for a construction material in responseto computer controlled data. U.S. Pat. No. 7,896,639 is incorporatedherein by reference. Using one or more print heads, as described in theabove-referenced application, to dispense a conductive material eitherin the form of a powder, a binder, or a polymer, a conductive region canbe formed in a three-dimensional structure. Suitable conductive powders,binders, or polymers may include carbon nano tubes or fine metallicparticles or fibers that are dispensed through the printing heads so asto construct a conductive portion within a three-dimensional part.

U.S. Pat. No. 7,722,802, which is incorporated herein by reference,describes a powder based rapid generative prototyping method. Theteachings and methodology described in the '802 patent can be modifiedas described below in accordance with the present invention.

By controlling the sequential deposition of a conductive powdermaterial, which may include metals, conductive polymers, or a conductivecarbon substrate, a three-dimensional body having conductivity therethrough may be provided. Alternatively, a non-conductive powder may bedeposited in and bound together with selectively applied conductive andnon-conductive binder. In general, additive manufacturing (AM)represents a technology field that can be used to form three-dimensionalobjects for solid images. In general, AM techniques buildthree-dimensional objects, layer by layer, from a building medium usingdata representing successive cross-sections of the object to be formed.The four primary modes of AM include stereo lithography, lasersintering, ink jet printing of solid images, and fused depositionmodeling.

In accordance with the present invention, it is recognized that thepresent technology directed to using thin layers to form solidstructures can be modified such that a portion of the applied thinlayers may include conductive materials such as steel wool, copperfibers, other metal fibers, and non-metallic conductive substrates suchas carbon based materials including carbon nano tubes or conductivepolymers. Suitable conductive polymers which can be applied by one ormore of the methodologies described herein include variouslinear-backbone polymer compounds including polyacetylene, polypyrrole,polyaniline, and their co-polymers and which include various melanins.Included among suitable conductive polymers are poly(fluorine)s,polyphenylenes, polypyrenes, polyazulenes, polynaphthalenes,poly(acetylene)s, poly(p-phenylene vinylene), poly(pyrrole)s,polycarbazoles, polyindoles, polyazepines, polyanilines,poly(thiophene)s, poly(3,4-ethylenedioxythiophene), poly(p-phenylenesulfide), and combinations thereof. Depending upon the nature of theconductive polymer, suitable applicators can be used based upon thematerial of choice. Various binders including electrically-conductivematerials can also be added to the conductive polymers to enhance theuse, application, or electrical-conductivity properties.

By applying such conductive materials within a precise location andgeometry, a three-dimensional object having an electrical pathway therethrough can be provided. Using a similar approach, an electricallyconductive object may have an appropriate layer of non-conductivematerial added where needed as an insulator.

The present process allows for rapid production of a part and/or aprototype in which the electrical properties of the part may beevaluated as well as a more traditional mechanical attributes of thepart. The present invention lends itself to the production of integratedcircuits within a rapid prototype part of the formation of a rapidprototype circuit board. Any three-dimensional part that lends itself toproduction through AM processes may be modified such that a component ofthe three-dimensional structure is supplied through an electricallyconductive material. As a result, increased functionality of a prototypecan be provided. In addition, to the extent the AM is used tomanufacture production parts, technology allows an improved way ofsupplying three-dimensional parts which require defined pathways ofconductive and non-conductive regions.

The present process also lends itself to the production of parts thatare more difficult to reverse engineer. A traditional electrically wireddevice can easily be reverse engineered by tracing the wiringconfiguration. Even for parts that are concealed within a housing whichis designed to render inoperative if the housing is removed, reverseengineering can still be accomplished by the use of x-rays or otherimaging technology. For some products, the external housing can bemelted or dissolved in an effort to preserve the integrity of the sealedinterior portion.

The present invention is more resistant to reverse engineering. Whilex-rays can be used to determine varying density within the extrudedlayers, it is possible to provide additives to the various insulatingand detector materials such that the layers are not readily differentiatable using imaging technology such as x-rays. Absent imagingtechnology, a physical removal of layers is needed which is moredifficult and costly. It is possible to match to colors of the variousconductive and non-conductive portions such that visual reconstructionof various layers is not readily apparent.

As a result of using conductive and non-conductive materials havingsimilar densities and colors, one can make the reverse engineeringprocess much more complicated. Such capabilities are a useful aspect forcertain embodiments of the present invention.

Although preferred embodiments of the invention have been describedusing specific terms, devices, and methods, such description is forillustrative purposes only. The words used are words of descriptionrather than of limitation. It is to be understood that changes andvariations may be made by those of ordinary skill in the art withoutdeparting from the spirit or the scope of the claims of the presentinvention. In addition, it should be understood that aspects of thevarious embodiments may be interchanged, both in whole, or in part.Therefore, the spirit and scope of the invention should not be limitedto the description of the preferred versions contained therein.

The invention claimed is:
 1. A process of providing a three-dimensionalpart having selected areas of electrical conductivity andnon-conductivity comprising the steps of: supplying one of either arapid prototype extrusion machine or a rapid additive manufacturingmachine; extruding a three-dimensional part comprising a first portionwhich is electrically non-conductive and a second portion which iselectrically conductive, the second portion including a mixture of anon-conductive substrate with an electrically conductive substrate andwherein an x-ray additive is incorporated into at least one of theelectrical non-conductive portion or the electrical conducting portionsso that a resulting x-ray density of the non-conducting portions and theconducting portions is substantially uniform.
 2. A process of providinga multi-layered object having areas of electrical conductivity andelectrical non-conductivity comprising the steps of: forming a substrateby the deposition of multiple substrate layers; integrating within themultiple substrate layers at least one three-dimensional region of anon-conductive substrate and at least one three-dimensional region of aconductive substrate, the conductive substrate applied by one of theeither stereo lithography, laser sintering, ink-jet printing, or fuseddeposition and having an x-ray density substantially identical to anx-ray density of the non-conducting substrate; wherein the multi-layeredobject has a three-dimensional electrical conductive portion within thenon-conductive substrate.
 3. The process according to claim 1 whereinthe electrically conductive portion further comprises a conductivematerial selected from group consisting of metal fibers, steel wool,carbon, carbon nanostructures, carbon nano tubes, metallic powders,conductive polymers, and combinations thereof.
 4. The process of claim 2wherein the step of integrating at least one three-dimensional region ofa conductive binder further comprises providing a conductive substratecomprising a conductive material selected from the group consisting ofmetal fibers, steel wool, carbon, carbon nanostructures, carbon nanotubes, metallic powders, conductive polymers, and combinations thereof.5. The process according to claim 1 wherein the extruding step furtherincludes the step of combining a coloring agent to at least one of theelectrically conductive or the electrically non-conductive portions sothat a color of the conductive and non-conductive portions isessentially uniform.
 6. The process according to claim 2 comprising theadditional step of adding a coloring agent to at least one of thenon-conductive substrate or the conductive substrate such that the colorof the conductive and non-conductive regions are essentially uniform. 7.A process of providing a three dimensional object having a selected areaof electrically conductive portion and a selected area of anon-conducting portion comprising the steps of: supplying a rapidprototype extrusion machine; extruding a three dimensional objectwherein a first portion is electrically non-conductive and has an x-raydensity, the three dimensional object having a second portion which iselectrically conductive, the second portion having an x-ray densityequal to the x-ray density of the non-conducting portion.
 8. The processaccording to claim 7, wherein the three dimensional object has a uniformx-ray density achieved by adding an x-ray density additive.